Electrical system



' Oct. 1, 1946.

A. H. DICKINSON ELECTRICAL SYSTEM Filed June 19, 1943 FIGJ.

' ATTORNEY Patented Oct. 1, 1946 ELECTRICAL SYSTEM Arthur H. Dickinson, ScarsdalaN. llsassignor to. j International Business. Machines Corporation," New York, N. Y., a corporation of New York Application June 19, 1943, Serial. No.; 491,438

' This. application relates to electron tube circuits and is a continuation-in-part of my application Serial No. 314,767, filed January 20, 1940.

A general object of the invention is the provisionof a novel method. and'mea-ns to change the distribution of electrical effects in a circuit by ghgngi-Ilg the conductive status of an electron u e. I

Other objects of theinvention include the provisionxof: I

A novel method and means to control conductivity of a gas-filledelectron tube.

A novel circuit with impedance branches bridgedby an electron tube to change the voltage. distribution at points of the impedance branches when current flow in the tube is changed.

Electron valvin mean-s to valve control potentials to electrodes of a gas-filled tube to control shutting off and ignitionofthe tube.

Electron impedances. arranged as voltage dividers to which electrodes of a gas-filled tube are connected, such imepdances bein varied by controlfpotentials togovern operation of the gasfilledtu-be.

Parallel voltage dividers, at least one of which includes an electron impedance, between which the cathode and anode ofa gas-filled tube are interposed, with the impedance being varied in value by a control potential to shut off the gasfilled tube.

Another general object of the invention isthe provisionof a novel method and-means whereby a circuit maybe varied in condition of stability under control of the circuit itself.

Means whereby concurrently activated iiiring and" extinguishing controls fora gas'fil.led tube are limited to non-concurrent action upon the, *tube.

Means Wherebyfiringand extinguishing con trol means for a gas-filled. tube are made effective by successive pulses to successively fire and extinguisli the tube.-

:Means whereby a single control pulse is efiec-' 19 Claims. (01. sis- 205i Further, an object of theinvention. is the,pro-' 4o Other objects of the .invention include provision-of: I I

tive eitherto fire or extinguish a gas-filled tube depending on Whether the tube at the time the pulse is applied is in a non-conductive or con- Means whereby a single electron valve is operated to alternately fire andshut off a gas tube by successive control pulses.

Delay means whereby application to firing'and extinguishing means, of a single controlpulse or of concurrently applied control pulses, isfprevented from effecting more than one change in the state of a gas tube.

Other objects of the inventiongwill be pointed out in the following descriptionand claims and illustrated in the accompanying drawing, which discloses, byway of, example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawing:

Fig. l is a circuit diagram of an elemental form of the invention,

Fig. 2 is a circuit diagram of an advanced form of the invention, and I Fig. 3' is a circuit diagram of a modification of the form of invention shown in Fig. 2.

The circuits shown in Figs. 1 and 2 are similar to circuits-included in my aforementioned copending application. For convenience, the parts of Figs. 1 and 2 Will be given the same reference characters as similar parts of the circuits in' the copending application.

Referring to Fig. 1 potential is continuously applied from a suitable D. C. source to plus and minus lines I and 2. Interposed between lines I and 2 are a plurality'oi parallel impedance sections comprised of; voltage dividers. .A first said voltage divider is a resistance 43. Resistance 43 is tapped by a connection to the anode ofgas-fllled tube-55 which i's of the three-element; type.- The cathode of this tube is connected to point 28' of a second voltage divider comprised of resistances designated 29- and 30.

The value of impedance 29 exceeds that of impedance 30 so that point 28 is relatively near the potential of line 2 When both ,of tubes 39a and 39 001 the. first voltage divider are at relatively high impedance, point 451s relatively near the potential of line 1... In other words, underthis condition, the impedance values are such that .thepotential"difference between points 45 and 28 approaches that between lines 1 and 2 and supplies ionization potential for gas tube 55, but thertu'be will remain shut off until its grid bias increasing their impedance.

control purposes.

is reduced. It will be noted that the potential at point 28 is the cathode potential. The grid of ga triode 55 is connected via protective resistance 31 to a point 48 of a third voltage divider. This voltage divider comprises a resistance designated 4%, a vacuum tube 42a, and a resistance 4|. Resistance 4| is a self-biasing resistance for tube 42a and normally maintains relatively high grid bias for the tube, so that the tube impedance is high. Under this condition, the potential of point 48 is closer to that of line 2 than is the potential of point 28. Since point 28 is connected to the cathode of gas triode 55 and point 48 is connected to its grid, the potential difierence between these points is the grid bias for the ga triode. Thus, under normal condition, with point 48 nearer than point 28 to the potential of minus line 2, the grid bias of the gas triode 55 is high, and it will remain extinguished. This third voltage divider-40, 42a, ll-constitutes a firing control section for the gas tube 55. When it is desired to fire the gas tube, positive potential from a suitable source is applied to a resistance 41 which is connected to the grid of vacuum tube 42a. As a result, the grid bia of the tube 420. is reduced, decreasing the impedance of the tube, so that current fiow in the third voltagedivider increases. Poirg; 48 thereupon rises in potential sufficiently to reduce the grid bias of the gas tube 55 to the firing value. Since ionization potential also is being applied to the gas tube, the tube will fire and conduct current between points 45 and 2B, respectively of the first and second voltage dividers. After ignition of the gas tube, its grid loses control. Hence, potential'may be removed from resistance 41 to permit the impedance of the tube 42a to be increased.

With gas tube 55 now conductive, the electrical conditions at various points of the circuit are changed. The ignition of the tube 55 has, in effect, conductively connected points 45 and 28. Thus, there is increased current flow through resistors 38 and 3D. The result is a rise in potential of point 28 and a, drop in potential of point 45. The decreased potential of point 45 reduces the plate voltage of tubes 39a and 391), further This reacts on the point 45 to raise its potential, compensating to some degree for its drop of potential resulting from conductivity of the gas triode 55. The net effect is that while the potential of point 28-has risen, the potential difference between points 45 and 28 is still high enough to maintain ionization of the gas, triode. As long as gas tube 55 is conductive, there is grid current flow through resistances 3'! and 4|. The potential at point 48 rises, increasing the self-bias of tube 42a, so that impedance of this tube, with potential now removed from resistance 41, increases above its initial value. Accordingly, the potential at any point along resistance 40 will rise. In brief, with the gas triode 55 ignited, the potential at any point along resistor 38 falls to some extent, and the potential of point along resistors 40,41, 29, and 3D rises. These changes may be utilized for To illustrate, simply, the effect of conductivity of the gas tube 55, Fig. 1 shows in dotted lines a work magnet or relay R which may be connected by a switch S between the cathode of the gas tube and point 28. With the gas tube conductive, magnet R will be energized 'to perform a desired task.

The firing ofthe gas tube 55 has been explained. Briefly, a voltage divider comprised of impedances 45, 42a, and 4i, of which 42a is a vacuum tube, serves as a firing control. The firing control operates upon a change in the vacuum tube impedance 42a resulting from application of a control pulse or potential to its grid.

The first voltage divider, comprised of resistances 38, andparallel tubes 39!; and 39b, acts as a selective extinguishing control for the gas tube 55. Each of the tubes 39a and 392) may be used to cause the gas tube to be extinguished. Positive potential applied to a resistance 44 will oppose negative potential applied by a battery 44a to the grid of tube 39a. The grid bias of tube 39a will thereupon be lowered, increasing current flow through resistance 38 and this tube, as a result of which the potential at point falls. The constants of this first voltage divider are such that the potential applied to resistance 44 will cause an amplified drop in potential of point 45. The decreased potential of this point reduces the potential on the anode of gas tube 55 below the ionization potential. Consequently, the gas tube is extinguished.

When it is desired to extinguish the gas tube 55 under control of tube 391), a switch I0 is opened. This places a resistance 224 in series with resistances 294 and 206 of a fourth voltage divider, so that the potential of a point 2l2 is raised. The point H2 is connected via a switch 12 to the screen grid of tube 3%. Now,'with the point H2 at increased potential, the screen potential of tube 391) is high enough to enable a reduction in its control grid bias to be effective. Such reduction in control grid bias takes place upon application of positive potential to a resistance 2350. The pulse on 2350 counteracts the effect of a battery 236 on the control grid of tube 391), reducing its grid bias. The increased conductivity of tube 391) has the same efiect as the increased conductivity of tube 39a in reducing the potential at point 45 and causing the gas tube 55 to be extinguished.

Pulses may be applied at successive times from different sources to'resistances 44 and 2350 to 45 cause tubes 39a and 39b to serve successively as or the closing of switch I0.

a pulse-valving device,depending on whether it is or is not desired to amplify the pulse appearing on resistance 41.

Fig. 2 shows another form of the invention which presents certainadvances over .the form 0 shown in Fig. 1. Similarly to the Fig. 1 circuit,

the circuit of Fig. 2 includes voltage dividers which have vacuum tubes varied in impedance by control pulses to fire and extinguish a gas tube. As with the Fig. l circuit, the firing of the gas tube in'the Fig. 2 circuit changes the electrical condition of various points of the circuit. An additional feature of the Fig. 2 :circuit involves means whereby concurrently pulsed firing and extinguishing controls nevertheless are caused to act singly; i. e., either the firing or extinguishing control is rendered effective at'any one time. Another feature of the Fig.2 circuit is means whereby the status of the circuit itself, which is dependent on the status of the gas triode, determines which of the concurrently pulsed firing and that point 536 rises in potential.

extinguishing controls is to'be effective. As will be pointed out, the gas 'triode when conductive enablesa control potential to act throughthe extinguishingcontrol to render thegas triode nonconductive, while the gas tube when extinguished enables control potential to act through a firing control to ignite the gas tube. Another feature ofthe'FigJ 2 circuit is delay means whereby'a single pulse, or concurrent pulses, will cause only onereversal of the statusof the circuit; i.e., of

the status-of the gas tube.

- In detail, '2 has a plus and minus lines I and 2 to which potential is applied from a directv current source. "Threevoltage' dividers are across the lines I and 2. The first voltage divider comprises resistance I 21' and pentode vacuum tube i282). These elements are similar to the resistmice 33 and tube 3% of the Fig. 1 circuit. A second voltage divider comprises resistances I23,

925a and resistance I255. These elements of the third voltage divider are similar to elements 40, 42a, andB of the firing control section of the Fig; 1 circuit.

With tube'IZSb at high-impedance, point I34 is near the potential of line I. The relation of the resistances I23, HI, and I22 is such that point I35 is near the potential of line. 2. Therefore, the'potential difierence between points I34 and I 35 approaches that between'lines I and 2 and is suificient to apply ionization potential to the gas tube, the tube, however, remaining shut off until its grid bias is reduced. The grid of the gas tube is connected via a' variable resistance I3I to the point 135 of thethird voltage divider. Resistance I26 is a self biasing control for tube Ia and maintains the tube at normally high impedance. Under this condition, point I36 is nearer than point I to the potential of line 2 and the grid bias of gas tube I29 is relatively high. Upon application of a positive potential to resistor IN, the grid bias'of tube I250, is reduced, decreasing the impedance of the tube, so As a result, the grid bias oi? gas tube I29 is lowered to the firing point. I

When the tube IE9 is conductive, there is increased current flow through resistances IZland I22. There is also grid cur-rent'fiow through resistances I3! and I26. flow through resistance I21 lowers the potential at point I3 1. The increased current flow in resistance I22 produces a rise in thepotential of points M3 and I35. The changes'in potentials of points 434 and I35 do not, however, reduce the potential difference between them below the re-, quired'ionization potential for the gas tube I29.

The rise in potential of point I33 increases the screen grid potential of the tube I 28b. Tube I 2231) thereby is prepared for a material change in impedance upon reduction of its control grid bias. The reduction of? control grid bias of the tube The increased current I "causing pointl l 34'to drop in potential to an extent such as to' cause the gas triode tobe extinguished. Y

Tubes] 28!), therefore,. serves asv an. extinguishing control in the same manner as; explained for tube 392) of Fig. 1. j. a

The changes in otential at various points of Fig., 2-:cir'cuit may .be utilized. for .ccntrolrpurposes in the same manner as the potential changes in'theFig. 1 circuit. In'addition, one control purpose in the Fig. 2 circuit is .to' self- 'condition the circuit,'as a result of ignitionof the gas tube, so as to prepare the gas tube to be shutoff.

Resistors I32 andIM may be connected, as indicated by the dotted line 430 toa single pulse source. In that event; bothi resistances I32 and I44 will be pulsed simultaneously from a common source and are equivalent to a single resistor tapped by connections to the grids of tubes I25a and I281)- On the other hand, resistances I32 and I 44 may be pulsed concurrently from separate sources. I

With resistances I32 an'd I44 pulsed simultaneously, the firing and extinguishing controls tend to act concurrently and counteract each other.

I However, when the'gas tube is extinguished, concurrent pulsing or the firing and extinguishing controls will first take effect upon the firing con-- trol since the screen voltage of the extinguishing control tube I281) is now at the lower of two values. The firing of the gas tube I29 causes the potential at point I43 to rise, but this rise is exponential owing to the presence of the condenser I23. The action of the condenser delays the rise in voltage of point I43 to prevent the screen potential of the pentode I281) from increasing to an effectivevalue until after the pulsing interval. Thus, tube I281) remains at high impedance, and point I34 at relatively high potential, until after the pulsing interval in whichthe g'astube'was fired. Accordingly, the gas tube I29. will not be re-extinguished in the same pulsing interval in which it was fired. Thus, delaymeans are pro- I 231) is eiTected upon application of a positive pulse to resistance I32 which counteracts the effect of the battery I33. Upon reduction of the grid bias of tube I281), its impedance is lowered,

vided whereby when the gas tube is shut off, pulses concurrently applied to the firing and extinguishing controls are effective only to ignite the gas tube. I

The delay means, comprising condenser I23, also serves for preventing the gas tube from being extinguished and re-fired during the same pulsing interval. Assuming the gas tube to be in a conductive state, point I i-3 is at high potential, so that the screen oftube I28b is maintained at high voltage. Thus, the next pulse applied to resistance I32 will be effective to reduce the impedance of tube I281) to such extent as'to reduce the potential at point I34below ionizationpotential. Accordingly, tube I 23 will be extinguished. The decrease in potential of point I33 resulting from increased current flow in tube I28b will be counteracted to some extent by the rise in potential of this point consequent upon the shutting off of the gas tube I29. Should points I43 and I35 drop instantly to their-lower poten- 'tials upon the shutting off of'the gas tube, the

screen voltage of tube 5281) will be lowered by the potential fall of point M3 to such extent that point 134Wi1lrise to ionization potential while the pulses are still acting concurrently on re- "sistances I32 and It' l.

pulse applied to resistancel id will produce a re duced grid bias for the gastube suffi-cient to refire .the gas tube. The, condenser I23,'however,

minus D. C. source lines.

7 serves to delay the fall in potential of points I35 and I43 upon the shutting off of the gas tube. As soon as points I 43 and I35 begin to drop in potential, condenser I23 which has been charged up to the potential obtaining between point I35 and line 2, commences to discharge through resistor I22. The discharge of the condenser tends to hold the points I35 and I43 at high potential. Accordingly, the screen voltage of tube I28b tends to remain high, so that its impedance will continue low and point 34 will be maintained below ionization potential. Further, the maintained high potential of point I35 counteracts the rise in potential of the grid of the gas tube which results from the pulse applied to the resistance I54 concurrent with the pulse on resistance I32. In other words, the discharge of the condenser serves to maintain a diiference in potential between points I35 and I36 which is sufiicient to prevent ignition of the gas tube even though a pulse is being applied to resistance I44.

The time taken for points I35 and I43 'to drop in potential when the gas tube is extinguished is determined by the time constant of resistance I22 and the condenser I23 and is such as to delay the drop of potential of these points exponentially until after the pulsing interval. The net result is that when the tube I29 is extinguished by a pulse on resistance I32, the points I43 and I35 will be maintained at increased potential and the point I34 at lowered potential at least for as lon as the pulses are acting concurrently on resistances I32 and I44. In other words, the gas tube will be held at low anode potential and high grid bias until after the shut-off pulse has ceased to act.

The foregoing has described a method and means for alternately firing and extinguishing a gas tube during successive pulsing intervals, in each of which a firing control and an extinguishing control are concurrently pulsed. As pointed out the Fig, 2 circuit has alternative conditions, and is self-governing so that when in either of these conditions, it enables control pulses or a pulse to reverse the condition. In other words, the condition of the circuit itself determines in which direction the condition of the circuit will be changed. Further, it has been explained that the gas tube when conductive will allow a pulse to shut oiT the tube and, when shut oil, will allow a pulse to ignite the tube. Thus, successive pulses will alternately fire and extinguish a gas tube under control of the tube itself. In the Fig. 2

circuit, the pulses or pulse were concurrently applied to two voltage dividers, one serving as a firing control for a gas tube and the other as the extinguishing control.

Fig. 3 shows a modification in which a single vacuum tube serves both as extinguishing and firing control means and in which the grid of the as tube remains at fixed potential while the cathode potential is reduced to cause ignition.

In detail, 5M and 502 designate the plus and Between these lines is a first voltage divider comprised of resistance 503 and pentode 505. The point 504 of this voltage divider connects via variable resistance 508 to the anode of gas-filled tube 509. The cathode of this gas tube is connected to point 5I6 of a second voltage divider, comprised of resistances 5M, 5I5, 5H, and condenser 5"! which shunts resistance 5II. The grid of gas tube 509 is connected via variable resistance 5| 0 to a point 5I2 of a third voltage divider comprising resistances5II and5l3.

.from a suitable source.

.520'is brought nearer line 502 in potential.

' As in the two previous embodiments, the values of the impedances are so related that, with tube 505 at high impedance, point 504 is relatively near the potential of line 50I and point 5I6 is nearer line 502 in potential. The difierence in potential between points 504 and 5I6 furnishes ionization potential for gas tube 509.

The values of the resistance of the second and third voltage dividers are so related that point 5 I2 normally is closerthan point 5 I6 to the potential of line 502. The difierence in potential between points 5I2 and BIG is the grid bias 'for thegas tube and normally is of sufiicient magnitude to prevent ignition of the gas tube.

The screen grid of tube 505 is connected to a point 520 of the second voltage divider. when gas triode 508 is in non-conductive condition, the potential at point 520 is at the lower of two possible values for this point. Accordingly, when the gas triode is in an extinguished status, the screen potential of thepentode 505 is at a relatively low value. The control grid of tube 505 isconnected to a bias battery 505 which has a connection to a resistor 50'! for receiving pulses It may be mentioned that, assuming the circuit constants to be substantially the same as in Fig. 2, the potential of pulses applied toresistor 501 of Fig. 3 should be higher than thatof a pulse or pulses applied to the resistors I32 and IM-of Fig, 2.

Assume that gas triode 509 is extingished, and a positive pulse is applied to resistor 501. Such pulse opposes bias battery 506, reducing the control grid bias of tube 505. In view of the relatively 10w screen potential of the tube 505, the

reduction of the control grid bias of this tube causes only a slight current rise through the voltage divider comprised of resistance 503 and the tube. This slight rise in current tends to reduce the potential at point 504 slightly. However, a second, controlling result of the decrease in grid bias of the tube 505 is an increase in screen grid current flow of this tube. As a result, point One effect of this is a lower screen potential for tube 505, so that its impedance increases, tending to maintain point 504 at its initial higher potential which it had before the pulse was applied to resistor 501. A second and principal effect of the lowered potential of point 520 is a reduction in current flow through resistors 5I5 and 5". Consequently, point 5I5 approaches closer to the potential of line 502. One result of such fall in potential of point 5I6 is that the potential difierence between this point and point 504 increases; i. e., the anode potential of gas triode 500 increases. A, second result of the drop in potential at point 5I5 is that the potential difference between this point and the point 5I2 of the third voltage divider is reduced; i. e., the grid bias of the gas triode 509 is decreased. The cumulative effect of the increase in anode potential and decrease of grid bias of the gas tube 509 is that the tube is ignited. After the tube is ignited, the control potential or pulse may cease to act on the resistor 501.

As in the other embodiments, with the gas triode in a conductive state, points 520' and 5I6 rise in potential, and such change may be utilized for control purposes. The change in potential at point 520 serves also to determine that the next pulse applied to resistor 50! shall extinguish the gas tube 509. Thus, with point 520 at the higher of its two possible potentials, the screen potential of pentode 505 is also relatively high. It

serving as part of-a voltage divider.

should-benoted that the higher potential at point 515, obtainingwhile the gas tube-is i'n conduc tive' condition, increases the grid bias of the gas tubeabove the critical value.- This ha no effect"- now; however, on the conductivity-of the gas-tube since the grid of the tube loses control when thetube is ignited. Assume, nowgthati-t is desired to extinguish the gas tube'55'9. Ajpulseis again applied to resistor M, reducing the controlgrid bias of the pentode. The two new concurrently operating factors, high screen" potential and re' duced grid bias or the pentode 505,- oombine to materially reduce its impedance.- The resulting increase in current flow through resistance 503 and pentode 505 causes point 504 to'drop in po-- tential to an amplified extent with respect to the arameter the control pulse applied to resistor 501. With point 504 at'the lowered potential, insuificient potential difference prevails -be-- tween the anode and "cathode-of the gas tube 509 to enable the 'tube to remain conductive. .Accordingly, the gas tube is extinguished Condenser 5l8in Fig; 3 has the same functimes condenser I23 in-Fig. 2. Briefly, it maintains point 520 at the higher-potential, after the- When, following extinction of the arc in the gas tube by onecontrol pulse, anext such 'pulsewill fire the gas-tube by causing a reduction in potential at oint 5 l5 and,hence, of'the cathode poten-' tial, in the manner described. The condenser I23 will maintain point 5 l 6 at lowe'redcathode potential and point 520 at lowered screen controlling petentialuntil aiter'the firing pulse has ceased to act.

The foregoing has described a method and means of firing and shutting off a gas triode by a pulse applied to a common point of the circuit and to--only one circuit elementanamely, a single variable impedance comprisedof a vacuum tube This single element of the circuit, 'in response to successive pulses applied at; a common point, will cause alternate firing and shutting off the .gas .triode.

The determination of whether "the single element shall respond to the pulse for firing the gas tube or for extinguishing-the gas tube is made by the circuit itselfin accordance with the-prevai-ling status of the gas tube. Thus, with the gas tube conductive, the single element will utilize the control pulse asan extinguishing pulse. On the other hand, with thegas tube in non-conductive state, the single element wilhapply the control pulse asa firing .pulse. The voltage divider including resistance- 583 andtube 505 serves as a combined firing and extinguishing control means for the gas tube. further, that the control pulse is effective, when the gas tr-iode is extinguished, to increase the potential between anode andficathode of the gas triode and-concurrently decrease its gridv bias so as to cause ignition. Further, it will be noted that the grid potentialofthe gastube remains substantilly "fixed and its 'grid'bias' is "varied by changing the potentialjo-f 'thei'ca thodei While there have been shown and described-and pointed out the fundamental" novel features of the invention as appliedto several embodiments,

it will be understood that various omissions and substitutions and "changes in. the fo'rm and de- It will be noted,

ITO?

tails of the devices illustrated and in their 0peration may be made by those skilled in the art, without departing from the ,spirit'of the invention. It is the intention, therefore, to be limited only as indicated by the scope of thefollowing claims.

What is claimed is:

1. An electrical system comprising a power source, parallel voltage dividers connected thereto, a gas-filled electron tube including anode, cathode, and grid electrodes and having the anode and cathode connected to points of two said dividers to bridgethem conductively-when ignited, said points being so chosen that cathode potential is lower than anode potential and high er than grid potential, said tube being ignited upon a reduction in potential dilference between cathode and grid and upon such ignition reducing charge tube in the voltage divider to a point of which the anode of the gas-filled tube is connected, said discharge tube upon applicationv of a pulse thereto being reduced in impedance and thereby causing current flow in the latter voltage divider to increase and reduce the potential at the anode-connected point below the value required to sustain ignition of the gas-filled tube.

3. An electrical system comprising a power source, and an electrical network'connected to saidsource and includingzparallel voltage dividers and agas tubeibridging said dividers, said tube including an anode electrode connected to a point of a first one of said dividers and a cathode electrode connected to a point of a second one of'said dividers and a control grid electrode at lower potential than the cathode potential, the diiierence in potential between cathode and grid electrodes being reduced by utilizing an. electrical pulse to changethe potential of one of the latter electrodes whereby thetube is ignited, said first voltage divider including a variable impedance electronic discharge device reduced in impedance by an applied potentialsov as to increase current flow in the first voltage divider and there 'by lower the potential at the anode-connected point below the value necessary to sustain ignition of the gas tube. I r

4. An electrical system comprising a power source, and an electrical circuit network connected to said source and including parallel volt- 1 age dividers and a gas tube including an anode connected to apoint of a first one of said dividers and a cathode connected to a point ofa second one of said dividers and also including a control grid normally at such bias-asto prevent ignition of the tube, means'torreducing the grid bias. so as to ignite the tubewhereby the distribution of "electrical values about the network is changedin such manner'as to reduce the po-:

' anode potential :below a :critical ignition-.sustaining'value; so that? the tube istextinguished to :BS-

11 tablish an alternative distribution of electrical values about the network.

5. An electrical system comprising a power source, and an electrical circuit network connected thereto and including parallel voltage dividers and a trigger tube having an anode and cathode and control grid, a connection from the anode tapping a chosen point of a first one of said dividers and a connection from the cathode tapping a chosen point of a second one of said dividers, said dividers being so proportioned and the points so chosen as to provide potential difierence between the anode and cathode sufficient to enable the tube to be triggered to a conductive state upon reduction of the cathode-to-grid potential, means whereby such reduction is effected, and means responsive to an electrical signal for increasing current flow in the first divider so as to reduce the potential at the tapped point thereof sufficiently to cause the tube to trigger back to a non-conductive state.

6. An electrical system comprising a power source, and a circuit network connected thereto and including parallel voltage dividers and a gas tube bridging the dividers, with an anode connected to a point of a first one of said dividers and a cathode connected to a point of a second one of said dividers, said points being so chosen as to provide suificient anode-to-cathode potential to maintain an arc in the tube after such are has been started, said tube including a starting grid normally below cathode potential, means for receiving electrical pulses and responding to one said pulse to reduce the potential difierence between cathode and grid surficiently to start an arc in the tube and responding to another pulse of the same polarity for reducing anode to cathode potential below arc-sustaining value, whereby the tube is alternated in condition by successive pulses of the same polarity.

'7. An electrical system comprising a power source, and an electrical circuit network connected to said source and including parallel voltage dividers and a trigger tube interposed between said dividers so as to establish certain electrical values about the network when in triggered state and other electrical values when in reverse state, said tube including an anode, cathode, and grid of which the anode and cathode are respectively connected to points of a first one of said voltage dividers and second one of said dividers so chosen as to apply sufiicient anode tocathode potential to enable the tube to be tripped to triggered state by reduction of grid bias and to maintain the tube in such state while the first mentioned electrical values prevail about the network, and means receiving an electrical pulse for reducing the potential at said point of the first divider to an extent depriving the anode of sufficient potential to maintain the tube in triggered state, whereupon the tube trips to reverse state and establishes said other electrical values about the network.

8. An electrical system comprising current supply lines and a circuit network supplied by said lines and including three parallel voltage dividers, a trigger tube having an anode connected to a point of a first one of said dividers to derive anode potential therefrom and having a cathode and control grid connected respectively to points of a second one of said dividers and third one of said dividers, means impressing acontrol potential upon the circuit network to react on one 01 the latter two dividers to reduce the potential difiererice between the grid and cathode to an extent such as to trip the tube from a nonconductive state to a conductive state, and means for reducing the potential at said point of the first divider to an extent such as to lower the anode potential below, a value required to maintain the tube conductive, whereby the tube trips to its non-conductive state.

9. An electrical system comprising a power source and an electrical network connected thereto and including a pair of parallel voltage dividers and a gas-filled trigger tube bridging points of said dividers, one of said dividers including parallel variable impedance electronic discharge devices, either of which upon a change in its impedance alters the potential at said point of the latter divider to such extent as to change the status of the tube, and means for rendering said discharge devices selectively effective, in response to electrical pulses applied thereto, to thus alter the potential at said point of the latter divider.

10. An electrical system comprising a power source, and an electrical network connected thereto and including parallel voltage dividers and a gaseous discharge tube bridging said dividers, with an anode connected to a point of one said divider and a cathode to a point of another said divider, said tube also having a control grid normally biased to prevent ignition of the tube and reduced in bias to cause ignition of the tube, said tube upon being ignited changing the distribution of electrical values about said network, a variable impedance electronic discharge device prepared by such change for responding to an electrical pulse to reduce the anode to cathode potential of the gaseous discharge tube below ignition-sustaining value, and means for applying said pulse to said discharge device to effect its response, after being prepared therefor, so as to reduce the anode to cathode potential below ignition-sustaining value for the gaseous discharge tube.

11. A circuit comprising a pair of impedance branches, a gas-filled tube bridging said branches and including a control grid, one said branch including a variable impedance electronic discharge device, the constants of said circuit being so adjusted that upon an alteration in impedance of the discharge device the tube is quenched, means for applying potential to said grid tending to ignite the tube and concurrently applying poten tial to said discharge device tending to quench the tube, and means controlled by the electrical condition of the circuit itself, and including delay means, for rendering only the discharge device or the grid effective to act in response to the concurrently applied potential to efifect its function.

12. .A self -governing circuit comprising a pair of impedance branches, a gaseous discharge tube bridging-said branches and including a control grid, one said branch including a variable impedance electronic discharge device efiective upon reduction of its impedance to quench the tube, means for applying potential to the discharge device tending to reduce its impedance and quench the tubeand concurrently applying potential to the control grid tending to ignite the tube, and means controlled by the tube itself, and including delay means, for selectively rendering the potential effective when the-tube is in a non-conductive status to act through said grid to ignite the tube and effective when the tube is in conductive status to act through said discharge device to extinguish the tube. I i i 13. An electrical system comprising a power source and an electrical network connected thereto and including parallel impedance branches and a gaseous discharge tube bridging said impedance branches and effective when in a conductive state to produce a desired potential at a point of one said impedance branch, a variable impedance electronic discharge device including a control electrode connected to a pulse applying means and another control electrode deriving potential from said point and effective when said point is at said desired potential toenable the pulse applied to the first'electrode to efiectively change the impedance of the device, said device being so connected into the network as to extinguish the tube upon said change in impedance.

14. A circuit comprising current supply lines, a gas-filled trigger tube including anode, cathode, and grid electrodes, means so connecting the electrodes to the supply lines as normally to provide sufiicient anode-cathode ionization potential and cathode-grid potential above tripping value, a variable impedance electronic discharge tube so connected into the circuit and to said gas-filled. tube as to be effective in response to a first electrical pulse to reduce the cathodegrid potential and trip the tube to ionized state and in response to a following pulse to reduce anode-cathode potential toquench the tube, and means for applying said pulses successively to the electronic discharge tube so as to effect such successive alternations in the status of the gas-filled tube.

15. A circuit comprising current supply lines, an impedance bridging said lines, and means for alternately increasing and reducing potential at a point of said impedance comprising a single variable impedance electronic discharge tube hav- 1 ing anode and cathode electrodes connected to said lines and including a screen grid connected to said point and also including a control grid, means for applying successive pulses of the same polarity to said control grid, one such pulse being eilective when the screen grid is at high potential to materially increase current flow in the tube and another such pulse being efiective when the screen grid is at low potential for increasing screen grid current flow, and means responsive to the increase in current flow of the tube for reducing the potential at said point and responsive to the increased screen grid current flow for increasing the potential at said point, whereby successive pulses of th same polarity applied to said control grid effect successive opposite changes in potential at said point.

16. A circuit network comprising a gas filled trigger tubeincluding an anode and a cathode, a variable impedance electronic tube including an anode, cathode and a plurality of control electrodes, means connecting the anode of the variable impedance tub to the anode of the trigger tube, means connecting a first one of said electrodes to the cathode of the trigger tube, means for applying successive pulses of the same polarity to the second one of said electrodes, one of said pulses reacting upon the first electrode to reduce its potential and thereby to reduce the cathode potential of the trigger tube sufilciently to cause its ignition, said trigger tub upon ignition increasing the potential of the first electrode whereby a succeeding one of said pulses by reason of the higher potential of the first electrode sufiiciently reduces the impedance of the variable impedance electronic tube to thereby reduce the anode potential of the trigger tube sufficiently to extinguish the trigger'tube.

17. A circuit comprising a gas-filled electronic trigger tube including anode, cathode, and grid electrodes, a variable impedance electronic discharge tube, means electrically connecting the discharge tube into the anode-cathode circuit of the trigger tube so as to quench the trigger tube upon a change in impedance of the discharge tube, said discharge tube including a control electrode connected to the output of the trigger tube and varying in potential in accordance with the quenched or ignited status of the trigger tube, and control means in the discharge tube responsive to successive electrical pulses for cooperating with the control electrode when the trigger 18. In combination, a gaseous discharge de-' vice with an anode and a cathode and a grid, a first electron emission device, a power source therefor, means for adjusting the electronic fiow from said source through said emission device, means conductively connecting said cathode to said power source, means connecting said anode and said electron emission device so that anode potential is altered upon adjustment of said electronic flow, a second electron emission device connected to said source, means for altering electronic flow from said source through the second emission device, means conductively connecting said grid and the second emission device so that grid potential is altered upon adjustment of electronic flow through the second emission device, said gaseous'discharge device being ignited upon said alteration of the grid potential and quenched upon said alteration of the anode potential.

19. An electrical flip-flop circuit including a plurality of resistors forming a voltage divider, a plurality of impedances including an electron emission device forming a second voltage divider, means electrically connecting said electron emission device to said first divider, a gaseous discharge device, means electrically connecting said gaseous discharge device to each of said voltage dividers, control means to which successive voltage impulses are applied, and means, including said electronic device and a condenser shunting one of said resistors, for alternately igniting and quenching said discharge device upon successive applications of voltage impulses to said control means whereby said desired potential is produced only upon each second application of said potential.

ARTHUR H. DICKINSON. 

